1. Field of the Invention
The present invention relates to a liquid supplying apparatus and an image forming apparatus and, more specifically, to a mechanism for identifying a cartridge needing to be replaced when the remaining amount of ink is below a prescribed value.
2. Description of the Related Art
As is generally known, printers, facsimile machines, copiers, and image forming apparatuses having plural such functions are configured to use a liquid droplet ejection apparatus having a recording head composed of a liquid ejection head that ejects liquid droplets such as ink.
The liquid droplet ejection apparatus attaches liquid droplets ejected from the recording head to a recording medium such as a recording sheet or causes the liquid droplets to permeate into the recording medium to form an image.
Note that examples of the recording medium include, besides the recording sheet described above, materials such as fibers including threads, leather, metal, resin, glass, wood, and ceramic allowing the attachment or permeation of liquid.
The liquid droplet ejection apparatus is provided with a liquid supplying apparatus that supplies ink from an ink cartridge acting as a main tank to a sub-tank provided in a carriage equipped with the recording head via a supplying tube or the like.
In order to allow image formation with plural colors, the liquid supplying apparatus may have plural of the ink cartridges provided corresponding to the plural colors.
Meanwhile, an ink cartridge is a member needing to be replaced when the remaining amount of the ink stored in the ink cartridge is below a prescribed value.
Up until now, the following method has been known as a method for identifying an ink cartridge needing to be replaced among those provided in a liquid supplying apparatus.
Assuming that an ink jet printer is an on-demand type that is used while being connected to a personal computer or the like, when the remaining amount of ink in any of plural ink cartridges is detected to be zero, information on the empty state of the corresponding ink cartridge is displayed on the display of the personal computer acting as an image information output unit connected to the color ink jet printer.
After confirming the display of the personal computer, a user leaves his/her desk to access the ink jet printer, opens the cover of the ink jet printer, and removes the ink cartridge of the color concerned among those arranged side by side so as to be replaced.
At this time, if the user does not exactly remember the color of the empty ink cartridge displayed on the personal computer, he or she may erroneously remove another of the ink cartridges.
In order to prevent this problem, it is possible to provide a light source near the installation position of ink cartridges of a printer main body so that the user is alerted to replace any of the ink cartridges when confirming the lighting or blinking of the light source.
However, since the user may not fully understand what the lighting or blinking of the light source indicates, i.e., the user may not fully understand whether the ink cartridges have become empty or still contain sufficient amounts of ink with this configuration of the ink jet printer, he/she may remove one of the other ink cartridges.
In order to solve such a problem in the replacement of an ink cartridge, Patent Document 1, for example, has proposed a printer that automatically unloads an empty ink cartridge and then loads a new ink cartridge provided by a user into a carriage with an automatic loading mechanism.
In this case, however, since the automatic loading mechanism must be specially provided inside the printer, the printer suffers from its complicated structure and high cost.
In addition, the connection joint of the ink cartridge and the connection joint of a printer main body are separated from each other in the printer. Therefore, the leakage of ink, the mixing of air bubbles or dust into an ink supplying path if a user does not immediately replace the ink cartridge, and a problem in an ink supply function due to the ink being dried may be caused.
In order to solve such problems, Patent Document 2, for example, has proposed an ink cartridge the joint of which is not separated from the joint of a printer main body, the ink cartridge being configured to have its outer shape deformed with a unit that operates an actuator or the like when the remaining amount of ink is detected to be zero so that a user is allowed to visually check the ink cartridge to be removed.
On the other hand, Patent Document 3, for example, has proposed an ink container configured such that a main chamber and a sub-chamber having a bellows are connected to each other via a branch flow path, the constriction operation of the bellows is induced by the outflow of ink from the sub-chamber when ink inside the main chamber decreases with the outflow of the ink from the main chamber, and engagement with the holding part of a cartridge is released via a member that operates simultaneously with the constriction operation of the bellows, whereby the cartridge can be unlocked by a member that decreases its volume with the consumption of the ink and be replaced.
The ink cartridge disclosed in Patent Document 2 allows the user to visually check the cartridge needing to be replaced but requires the actuator or the like to check the cartridge. Therefore, since the ink cartridge requires, as in the printer disclosed in Patent Document 1, a detection unit that detects whether the ink cartridge has become empty and an operations unit such as a special actuator acting as a trigger for detecting the empty state of the ink cartridge and deforming the outer shape of the ink cartridge, problems in the complicated structure of the mechanism of the ink cartridge and high cost are not still solved.
Further, the ink container disclosed in Patent Document 3 uses the member that decreases its volume with the consumption of the ink to unlock and replace the cartridge, which in turn eliminates the use of a mechanical component such as the actuator or the like disclosed in Patent Document 2. Therefore, reduction in component cost can be attained.
However, the ink container disclosed in Patent Document 3 is configured to, as the ink outflows from the sub-chamber with the consumption of the ink, move a locking release member in accordance with a change in the constriction operation of the bellows forming the sub-chamber to release engagement with a locking member, and configured to bias the cartridge to be ejected outside when the cartridge is unlocked. Therefore, the ink cartridge is configured to be locked during its ejection process when the locking member faces the engagement part of the bellows again. As a result, the ejection of the cartridge may be interrupted.
Moreover, after the release of the engagement, the cartridge itself must be ejected. Thus, although a force for biasing the cartridge to be ejected is substantially large, the upsizing and complexity of an apparatus due to the provision of a biasing force application unit are inevitable.
Further, the ejected cartridge may take outside air or foreign matter into it because the bellows of the sub-chamber cannot maintain a constriction position due to its shape restoration force. If the outside air or the foreign matter is taken into the ejected cartridge, there is a problem in the reuse of the cartridge and the ink container is disadvantageous in terms of environmental protection.
Patent Document 1: JP-A-2007-69541
Patent Document 2: JP-A-2009-39870
Patent Document 3: JP-A-2009-83290